78. Emission factors for passenger rail services have been updated and provided in Table 26. These include updates to the national rail, international rail (Eurostar), light rail schemes and the London
Underground. Emission factors for CH4 and N2O emissions were also
updated in the 2010 GHG Conversion Factors. These factors are based on the assumptions outlined in the following paragraphs. International Rail (Eurostar)
79. The international rail factor is based on a passenger-km weighted average of the emission factors for the Eurostar London-Brussels and London-Paris routes. The emission factors were provided by Eurostar for the 2010 update, together with information on the basis of the electricity figures used in their calculation.
80. The methodology applied in calculating the Eurostar emission factors currently uses 3 key pieces of information:
a. Total electricity use by Eurostar trains on the UK and France/Belgium track sections;
b. Total passenger numbers (and therefore calculated passenger km) on Eurostar London-Paris and London-Brussels services;
c. Emission factors for electricity (in kgCO2 per kWh) for the UK and
France/Belgium journey sections. These are based on the UK grid average electricity from the Defra/DECC GHG Conversion Factors and the France/Belgium grid averages.
81. Eurostar's published figure is 7.71 gCO2/pkm. This differs from the
figure quoted in the 2010 GHG Conversion Factors as it is calculated using the individual conversion factors as specified by each electricity supplier across each network section upon which they operate, rather than the grid average. More recent data was not available for the 2011 update. For further information please visit:
http://www.eurostar.com/UK/uk/leisure/about_eurostar/environment/gre ener_than_flying.jsp
82. CH4 and N2O emission factors have been estimated from the
corresponding emissions factors for electricity generation, proportional to the CO2 emission factors.
National Rail
83. The national rail factor refers to an average emission per passenger kilometre for diesel and electric trains in 2007-08. The factor is sourced from information from the Office of the Rail Regulator‘s National rail trends for 2007-8 (ORR, 2009)30. This has been calculated based on total electricity and diesel consumed by the railways for the year (sourced from ATOC), and the total number of passenger kilometres (from National Rail Trends). The factor for conversion of kWh electricity into CO2 is based on the 2006 grid mix (the most recent figure available
at the time). No newer dataset was available for the 2011 update. 84. CH4 and N2O emission factors have been estimated from the
corresponding emissions factors for electricity generation and diesel rail (from the UK GHG Inventory), proportional to the CO2 emission factors.
The emission factors were calculated based on the relative passenger km proportions of diesel and electric rail provided by DfT for 2006-7. Light Rail
85. The light rail factors were based on an average of factors for a range of UK tram and light rail systems, as detailed in Table 25.
86. Figures for the DLR, London Overground and Croydon Tramlink for 2009/10 based on figures from Transport for London‘s 2010
environmental report31 adjusted to the new 2009 grid electricity CO2
emission factor.
87. The factors for Midland Metro, Tyne and Wear Metro, the Manchester Metrolink and Supertram were based on annual passenger km data from DfT‘s Light rail and tram statistics‘32
and the new 2009 grid electricity CO2 emission factor.
88. The factor for the Glasgow Underground was provided by the network based on annual electricity consumption and passenger km data provided by the network operators for 2005/6 and the new 2009 grid electricity CO2 emission factor, for consistency.
89. The average emission factor was estimated based on the relative passenger km of the four different rail systems (see Table 25).
30 Available from the ORR‘s website at:
http://www.rail-reg.gov.uk/upload/pdf/rolling-c9-environ.pdf
31 TfL, 2011. TfL‘s 2010 environmental report is available at:
http://www.tfl.gov.uk/corporate/about-tfl/publications/1478.aspx 32
DfT Light rail and tram statistics,
90. CH4 and N2O emission factors have been estimated from the
corresponding emissions factors for electricity generation, proportional to the CO2 emission factors.
Table 25: GHG emission factors, electricity consumption and passenger km for different tram and light rail services
Type Electricity use gCO2e per passenger km Million kWh/pkm CO2 CH4 N2O Total pkm DLR (Docklands Light Rail) Light Rail 0.131 68.3 0.033 0.498 76 365 Glasgow Underground Light Rail 0.164 85.6 0.041 0.531 86.2 42 Midland Metro Light Rail 0.135 70.5 0.034 0.437 71.0 50 Tyne & Wear Metro Light Rail 0.198 103.0 0.049 0.638 103.6 327 London Overground Light Rail 0.098 51.0 0.024 0.316 51.3 437 Croydon Tramlink Tram 0.085 44.3 0.021 0.274 44.6 134 Manchester Metrolink Tram 0.076 39.5 0.019 0.245 39.7 206 Nottingham Express Transit Tram No data No data No data
Supertram Tram 0.186 96.8 0.046 0.600 97.4 103
Average* 0.129 67.3 0.032 0.434 69.4 1664
Notes: * Weighted by relative passenger km
London Underground
91. The London Underground rail factor is from Transport for London‘s 2010 environmental report (TfL, 2011), corrected to the 2009 grid electricity CO2 emission factor.
92. CH4 and N2O emission factors have been estimated from the
corresponding emissions factors for electricity generation, proportional to the CO2 emission factors.
Table 26: Updated 2010 GHG emission factors for passenger rail travel
Rail gCO2e per passenger km Source*
CO2 CH4 N2O Total
International rail 15.0 0.010 0.090 15.1 Average figures from Eurostar for London to Brussels and Paris routes
National rail 53.4 0.060 3.030 56.5 Emission factor based on ORR (2009) Light rail
(and tram)
71.0 0.030 0.440 71.5 Average of UK light rail and tram systems London
underground
73.1 0.030 0.450 73.6 Transport for London‘s 2010 environmental report
Notes: * Source is for CO2 data only; CH4 and N2O emissions have been estimated by other means.